Release-18 (rel-18) support of two timing advances (tas) for single cell

Abstract

Systems, apparatuses, methods, and computer-readable media are provided for a user equipment (UE) in a new radio (NR) system to support two timing advances (TAs) in a single cell of a cellular network. In some embodiments, one or more of the TAs may be indicated to the UE by a base station (e.g., in a MAC RAR or a MAC CE). Other embodiments may be described and/or claimed.

1 . A base station comprising:
 one or more processors; and   one or more non-transitory computer-readable media comprising instructions that, upon execution of the instructions, are to cause the base station to:   identify that a serving cell associated with the base station belongs to two timing advance groups (TAGs);   generate an information element (IE) related to a configuration of the serving cell, wherein the IE includes a first identifier of a first TAG of the two TAGs and a second identifier of a second TAG of the two TAGs; and   transmit the IE to a user equipment (UE).   
     
     
         2 . The base station of  claim 1 , wherein the IE is a ServingCellConfig IE. 
     
     
         3 . The base station of  claim 1 , wherein:
 the first TAG corresponds to a first timing advance (TA) value and a first TA timer; and   the second TAG corresponds to a second TA value and a second TA timer.   
     
     
         4 . The base station of  claim 1 , wherein the first identifier is a tag-ID field of the IE, and wherein the second identifier is a tag-Id2 field of the IE. 
     
     
         5 . The base station of  claim 1 , wherein the instructions are further to cause the base station to transmit, to the UE, an indication that the first TAG is associated with a first transmission configuration indicator (TCI)-state identifier, and the second TAG is associated with a second TCI-state identifier. 
     
     
         6 . The base station of  claim 5 , wherein the indication is transmitted in downlink control information (DCI), radio resource control (RRC) signaling, or a medium access control (MAC) control element (CE). 
     
     
         7 . The base station of  claim 1 , wherein the instructions are further to cause the base station to identify, from the UE, a first signal based on the first TAG and a second signal based on the second TAG. 
     
     
         8 . A user equipment (UE) comprising:
 one or more processors; and   one or more non-transitory computer-readable media comprising instructions that, upon execution of the instructions by the one or more processors, are to cause the UE to:
 identify, from a base station of a serving cell that belongs to two timing advance groups (TAGs), an information element (IE) related to a configuration of the serving cell, wherein the IE includes a first identifier of a first TAG of the two TAGs and a second identifier of a second TAG of the two TAGs; and 
 perform cellular communication based on the first TAG and the second TAG. 
   
     
     
         9 . The UE of  claim 8 , wherein the IE is a ServingCellConfig IE. 
     
     
         10 . The UE of  claim 8 , wherein:
 the first TAG corresponds to a first timing advance (TA) value and a first TA timer; and   the second TAG corresponds to a second TA value and a second TA timer.   
     
     
         11 . The UE of  claim 8 , wherein the first identifier is a tag-ID field of the IE, and wherein the second identifier is a tag-Id2 field of the IE. 
     
     
         12 . The UE of  claim 8 , wherein the instructions are further to cause the UE to identify, from the base station, an indication that the first TAG is associated with a first transmission configuration indicator (TCI)-state identifier, and the second TAG is associated with a second TCI-state identifier. 
     
     
         13 . The UE of  claim 12 , wherein the indication is identified in downlink control information (DCI), radio resource control (RRC) signaling, or a medium access control (MAC) control element (CE). 
     
     
         14 . One or more non-transitory computer-readable media comprising instructions that, upon execution of the instructions by one or more processors of a user equipment (UE), are to cause the UE to:
 identify, based on a first random access channel (RACH) procedure to connect with a base station, a first timing advance (TA) of a first cell;   identify, based on a second RACH procedure that is performed after the first RACH, a second TA of a second cell;   communicate, after the second RACH procedure, with the first cell based on the first TA; and   communicate with the second cell based on the second TA.   
     
     
         15 . The one or more non-transitory computer-readable media of  claim 14 , wherein the second RACH procedure is based on an order received from the base station. 
     
     
         16 . The one or more non-transitory computer-readable media of  claim 15 , wherein the order is an element of a physical downlink control channel (PDCCH) transmission. 
     
     
         17 . The one or more non-transitory computer-readable media of  claim 15 , wherein the second RACH procedure is a contention-free RACH procedure. 
     
     
         18 . The one or more non-transitory computer-readable media of  claim 15 , wherein the order includes an indication of a dedicated RACH source or an indication of quasi co-location (QCL) information for use during the second RACH procedure. 
     
     
         19 . The one or more non-transitory computer-readable media of  claim 14 , wherein the first cell and the second cell are respectively associated with a first transmit/receive point (TRP) and a second TRP. 
     
     
         20 . The one or more non-transitory computer-readable media of  claim 14 , wherein the first cell and the second cell are cells of the base station.